Good looking bikes. I installed a big bore kit on MXTerri's son Justin's YZ125. It was an easy to do deal, even though I had to relieve the cases so the rod would clear. You could tell it had more displacement, but it wasn't enough to make a big difference when hauling my 160 pound butt around. Justin loved it, but he was 5'5" and around 130. If I was spending time and money on it I would go with the 250.